_____ are factors that are not tested and remain constant. A. Dependent variables B. Controlled variables C. Independent variables D. Constant variables
Answer:
B. Controlled variables
Explanation:
The Dependent sample t-test compares the mean score of measurements in one group to that of another other group. It mainly used when analyzing comparable sample units as it pairs repeatable observations within a time frame.
Controlled variables are factors that are not tested and remain constant. Some examples of controlled variables are temperature, pressure, volume etc
why can mosquitos stand on water?
A-The mosquito is able to walk on the water due to the attraction between multiple water molecules, creating surface tension.
B-The mosquito is able to walk on the water due to the attraction between water molecules and other non-water molecules, creating surface tension.
Answer:
Mosquitos can stand on water because;
A. The mosquito is able to walk on the water due to the attraction between multiple water molecules, creating surface tension
Explanation:
Surface Tension is the surface property of a liquid which is due to the cohesive forces of attraction between its molecules, that enables it to withstand an external shearing force
The molecules in a liquid maintain a cohesive force between adjacent molecules that keeps all the molecules together such that the liquid has a defined volume
On the surface of the liquid, the cohesive forces between the molecules are shared by only between the adjacent molecules and molecules which are under the surface, and therefore, the attraction is much stronger such that the surface of the liquid is in tension, which is called the surface tension of the liquid
Therefore, the mosquito is able to walk on the water due to the attraction between multiple water molecules, creating surface tension.
Compounds that are ductile and excellent conductors of electricity have *
covalent bonds.
ionic bonds.
isotopic bonds.
metallic bonds.
Answer:
metallic bonds.
Explanation:
Generally, compounds that are ductile and excellent conductor of electricity have metallic bonds between them.
These compounds are usually metals.
Metallic bond join that atoms of metals and alloys together. The formation of this type of bond is favored by large atomic radius, low ionization energy and a large number of electrons in their valence shell. The physical properties of metals like ductility, malleability, electrical and thermal conductivity all results from metallic bonds.
2 H2 + O2 → 2 H20, how many moles of O2 are needed to yield 7.8 moles of
water?
Answer:
12 moles H2O
Explanation:
Your tools of choice for stoichiometry problems will always be the mole ratios that exist between the chemical species that take part in the reaction.
As you know, the stoichiometric coefficients attributed to each compound in the balanced chemical equation can be thought of as moles of reactants needed or moles of products formed in the reaction.
In your case, the balanced chemical equation for this synthesis reaction looks like this
2H2(g]+O 2(g]→2H2O(l]]
Notice that the reaction requires
2
moles of hydrogen gas and
1
mole of oxygen gas to produce
2
moles of water.
This tells you that the reaction produces twice as many moles of water as you have moles of oxygen gas that take part in the reaction.
You know that your reaction uses
6.0
moles of oxygen. Assuming that hydrogen gas is not a limiting reagent, you can say that the reaction will produce
6.0
moles O
2⋅2
moles H
2O1
moles O
2=
12 moles H2O
How can calcium oxide change directly to limewater?
Wants equation and observation
Answer:
Lime(Calcium Oxide) is a white solid with strongly basic properties.Lime reacts readily with water to produce slaked lime,which is the chemical compound calcium hydroxide.....
When carbon dioxide gas is passed through or over limewater,it turns milky due to the formation of calcium carbonate.
what are alkenes and there chemical property
Answer:
Alkenes contain a double bond that is composed of one sigma and one pi bond between two carbon atoms. The sigma bond has similar properties to those found in alkanes , while the pi bond is more reactive. The carbon atoms in the double bond are sp² hybridized , forming a planar structure.
Explanation:
Believe it!!!
What is the product(s) in the reaction below?
Answer:
imma go with the answer B
The product in the reaction [tex]\rm Zn + 2HCl \rightarrow[/tex] is [tex]\rm ZnCl_2 + H_2[/tex]. The correct answer is option D.
A reaction is a process that involves the transformation of one or more substances into one or more different substances.
The reaction between zinc (Zn) and hydrochloric acid (HCl) is a classic example of a single displacement reaction. In this reaction, zinc reacts with hydrochloric acid to produce zinc chloride ([tex]\rm ZnCl_2[/tex]) and hydrogen gas ([tex]\rm H_2[/tex]).
The balanced chemical equation for this reaction is:
[tex]\rm Zn(s) + 2HCl(aq) \rightarrow ZnCl_2(aq) + H_2(g)[/tex]
Therefore, the product of the reaction between zinc and hydrochloric acid is zinc chloride ([tex]\rm ZnCl_2[/tex]) and hydrogen gas ([tex]\rm H_2[/tex]). Option D is the correct answer.
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Question 1
Review
Which laboratory equipment is correctly paired with the unit it measures?
Answer:
Cilindros graduados
Explanation:
Son una herramienta de medición primaria para el volumen de un líquido, y tiene varias marcas hacia arriba y hacia abajo a lo largo del contenedor con incrementos específicos. Los cilindros graduados vienen en muchos tamaños; entre más pequeños sean de diámetro, más específicas serán las mediciones de volumen. Al leer el volumen de un cilindro graduado, notarán que el líquido parece tener una muesca; el líquido alrededor de los bordes será más alto que el líquido en el centro, inclinándose hacia abajo como los lados de un trampolín cuando alguien está parado en el medio. Esto se llama el menisco. Alineen el punto más bajo del menisco con la marca más cercana, manteniendo el nivel del cilindro para leer correctamente el volumen.
What is the molar mass of carbon?
1. Why was a mole created?
Answer:
Avogadro proposed that equal volumes of gases under the same conditions contain the same number of molecules, and hypothesis that proved useful in determining atomic and molecular weights and which led to the concept of mole.
Explanation:
"The mole is important because it allows chemists to work with the subatomic world with macro world units and amounts. Atoms, molecules and formula units are very small and very difficult to work with usually. However, the mole allows a chemist to work with amounts large enough to use."
- Source socratic.org
Hope this helped!
There can be four equivalent best resonance structures of
A.NO3
B.S032-
C.PO43
D.NO2
E.CIO3
There are four equivalent best resonance structures of (PO₄)₃ according to the concept of resonance.
What is resonance?
The phenomenon of resonance which is also called mesomerism is the ability of the molecules or ions to explain the bonding in them by the combination of several canonical structures.
It is an extension of Lewis structures to describe bonding in chemical species.The resonance structures also include the fractional charges present on the atom .They are capable of of depicting delocalized electrons which are unable to be depicted by single Lewis structure.
Molecules with extended pi system are well defined by resonance hybrids.It is a way of giving description of bonding in certain molecules.When there is passage of electrons through pi structures which are opposing ,resonance occurs.
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How many atoms of beryllium are equal to 0.39 moles of beryllium?
Answer:
2.35 x 10²³atoms
Explanation:
Given parameters:
Number of moles of Be = 0.39moles
Unknown:
Number of atoms = ?
Solution:
To solve this problem:
1 mole of a substance contains 6.02 x 10²³ atoms
0.39 mole of Be will contain 0.39 x 6.02 x 10²³ = 2.35 x 10²³atoms
A 1,600-milliliter bucket of paint is at a temperature of 70°F. Then the paint is divided equally into four smaller buckets. Each bucket is at 70°F before the paint is poured. The temperature of each bucket is about _____ the temperature of the original bucket of paint. a. The same as b.Four times c.One-fourth
Answer:
Same.
Explanation:
The temperature of each 400mL bucket is about the same as the temperature of the original bucket of paint.
This is because the temperature is an intrinsic property.This means that temperature is independent of the quantity of matter. Therefore, the temperature of paint inside the bucket is not dependent on the amount of paint present.
Which is the most common type of precipitation?
hail
rain
sleet
snow
Answer:
rain I think
Explanation:
Precipitation mostly relies on the main source water, that is how snow hail, and other cool weather form are created. So rain I may be wrong.
,
Rain is the most common type of precipitation. Therefore, the correct option is option B among all the given options.
What is precipitation?Any liquid and frozen water which condenses in the atmosphere then falls to the ground is referred to as precipitation. Rain, sleet, as well as snow are only a few of its various manifestations. Precipitation is one of three main processes that make up the global water cycle, together with evaporation and condensation.
Water vapor in the clouds condenses into increasing-sized droplets of water, forming precipitation. The drips hit the ground when they are sufficiently hefty. The water droplets can freeze to produce ice if a cloud is colder, as it would be at higher elevations. Rain is the most common type of precipitation.
Therefore, the correct option is option B.
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A student noticed that the size of the hot pack becomes bigger when magnesium sulfate reacts with water. She thinks that more atoms are produced that make the hot pack grow bigger. Do you agree? Explain.
Answer:
Disagree with the suggestion based on the hygroscopic nature of anhydrous magnesium sulfate
Explanation:
Magnesium sulfate in the anhydrous form is a drying agent. A drying agent salts of inorganic compounds that has the capability of absorbing water to become hydrated, when placed in the presence of a wet surface or moist air
Anhydrous magnesium sulfate is therefore hygroscopic such that it absorbs water from the atmosphere and becomes hydrated and increases in size as its volume is increased according to the following chemical equation
MgSO₄(s) + 7H₂O(l) → MgSO₄·7H₂O(s)
The molar mass of anhydrous magnesium sulfate = 120.366 g/mol
The molar mass of the heptahydrate = 246.47 g/mol
Therefore, the mass of the magnesium sulfate doubles when it forms the heptahydrate, and the magnesium sulfate grows bigger.
Which statement best describes the use of catalytic converters in automobiles?
They decrease the rate of the reactions that produce harmful gases.
They oxidize hydrocarbons to form less toxic gases.
They combine the larger hydrocarbon molecules with smaller ones.
They increase reaction temperature for cleaner burning.
Answer:
The statement that best describes the use of catalytic converters in automobiles is;
They oxidize hydrocarbons to form less toxic gases
Explanation:
Catalytic converters
A working engine produces some air pollutants which are made due to fuel not completely burnt in the engine, including unburnt gasoline (a hydrocarbon), nitrogen oxides, and carbon monoxide
Carbon monoxide is poisonous to breathe in if present in the air around us, and nitrogen oxides causes acid rain and smog, while hydrocarbon from the gasoline causes smog
The catalyst in the catalytic converters aids in the conversion of the harmful gases produced by the car engine into harmless gases such as the types of gases already existing in the atmosphere and therefore, can be released into the air
The catalysts in the catalytic converter work by either oxidizing some of the harmful gases such as the unburnt hydrocarbons, or by reducing the other harmful gases such as the nitrogen oxides.
Therefore, the statement that best describes the use of catalytic converters in automobiles is that they oxidize hydrocarbons to form less toxic gases
Answer:
b
Explanation:
got it right on test
What is the ratio of the lithium and the chlorine atoms in the compound? __________________
PLEASE ANSWER ASAP!!!!!!!!!!!! The Relative Surface Gravity is 27.551 on _____.
Saturn
the Moon
the sun
Jupiter
Answer:
its the sun
Explanation:
Estimate: Press Reset. Select Atoms, and using the slider, start with 1.000 × 1023 atoms of sulfur. (Note that pressing Start puts atoms into the atom counter, not the jars.)
Is this amount more or less than one mole?
Place the jar underneath the counter. Was the jar completely filled?
How many moles do you have?
Answer:
1) The amount is less than one mole, 2) The jar is not completely filled, 3) We have 0.166 moles of sulfur.
Explanation:
We proceed to respond each question below:
1) Is this amount more or less than one mole?
According to the Avogadro's Number, one mole of an element contains about [tex]6.022\times 10^{23}[/tex] atoms. Given that we have [tex]1.000\times 10^{23}[/tex] atoms, then we conclude that this amount is less than one mole.
2) Place the jar underneath the counter. Was the jar completely filled?
Let suppose that the jar can contain up to a mole of sulfur. Then, we conclude that jar is not completely filled.
3) How many moles do you have?
The amount of moles is determined by dividing the current amount of atoms by Avogadro's Number:
[tex]x = \frac{1.000\times 10^{23}\,atoms}{6.022\times 10^{23}\,\frac{atoms}{mole} }[/tex]
[tex]x = \frac{500}{3011}\,mole[/tex]
We have 0.166 moles of sulfur.
Please help quick
1) How much heat does 23.0 g of water absorb as its temperature increases from 25.4 °C to 42.8 °C?
2) A sample of unknown metal has a mass of 120.7 g. As the sample cools from 90.5 °C to 25.7 °C, it releases 7020 J of energy. What is the specific heat of the sample?
Answer:
c = 0.898 J/g.°C
Explanation:
1) Given data:
Mass of water = 23.0 g
Initial temperature = 25.4°C
Final temperature = 42.8° C
Heat absorbed = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Specific heat capacity of water is 4.18 J/g°C
ΔT = 42.8°C - 25.4°C
ΔT = 17.4°C
Q = 23.0 g × × 4.18 J/g°C × 17.4°C
Q = 1672.84 j
2) Given data:
Mass of metal = 120.7 g
Initial temperature = 90.5°C
Final temperature = 25.7 ° C
Heat released = 7020 J
Specific heat capacity of metal = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 25.7°C - 90.5°C
ΔT = -64.8°C
7020 J = 120.7 g × c × -64.8°C
7020 J = -7821.36 g.°C × c
c = 7020 J / -7821.36 g.°C
c = 0.898 J/g.°C
Negative sign shows heat is released.
The temperature of the system is highest when it is a
A. gas
B. liquid
C. plasma
D. solid
Answer:
gas
Explanation:
its either gas or plasma but gas should be it bc liquid and solid are cold
1. How many moles of HCl are in 7.80 X 1022 molecules? Answer:___0.13 moles of HCI
Answer: 7.80×[tex]10^{22}[/tex][tex]\frac{1}{6.02*10^{23} }[/tex] =.13
Explanation:
The number of moles that are present in 7.80 × 10²² molecules of HCl is 0.13 moles
What is the number of moles?The number of moles of a substance is defined as the mass of the substance divided by the molar mass of such a substance. Also, one mole of a substance is synonymous and equal to 6.023 × 10²³ Avogadro's number.
So, If 1 molecule of HCl = 6.023 × 10²³ molex molecules of HCl = 7.80 × 10²² molecules:Therefore, the number of moles that are present in 7.80 × 10²² molecules of HCl can be computed as:
[tex]\mathbf{=\Big(7.80 \times 10^{22} \times \dfrac{1}{6.02\times 10^{23} }\Big)\ moles}[/tex]
= 0.12956 moles
≅ 0.13 moles of HCl
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El salmón percibe la presencia del 2-feniletanol (C5H5-CH2-CH2-OH) en el agua, en cantidades tan bajas como 0.03 mole en cien trillones (1*10^18) de litros de agua, ¿cuál es la masa, en gramos, de esa sustancia? ¿Qué cantidad de moléculas equivale a esa sustancia?
Answer:
3.66 g de 2-feniletanol (C5H5-CH2-CH2-OH)
1.8 * 10 ^ 22 moléculas
Explanation:
Sabemos que podemos obtener la masa de una sustancia a partir del número de moles presentes de la siguiente manera;
número de moles = masa / masa molar
masa molar de 2-feniletanol (C5H5-CH2-CH2-OH) = 122,16 g / mol
masa = 0.03 moles * 122.16 g / mol = 3.66 g de 2-feniletanol (C5H5-CH2-CH2-OH)
Si 1 mol = 6.02 * 10 ^ 23 moléculas
0.03 moles = 0.03 moles * 6.02 * 10 ^ 23 moléculas = 1.8 * 10 ^ 22 moléculas
Identify this parasitic organism.
Answer:
Schistosoma or blood fluke
Explanation:
Parasitic organisms are defined as the organisms that depends on other organisms body called host for their nutrition and harm the host body.
The given image is of Schistosoma that is commonly known as blood flukes. Schistosoma are flatworms which causes group of infections in humans known as schistosomiasis. Schistosoma is a water-borne parasite and found in veins near the human intestine.
Hence, the correct answer is "Schistosoma or blood fluke".
PLEASE HELP!!
How many moles are present in 431.56 grams of sodium bicarbonate ( NaHCO3)?
Molar mass of sodium bicarbonate (NaHCO3) = 84.01 g/mol
Answer:
5.14mole
Explanation:
Given parameters:
Mass of sodium bicarbonate = 431.56g
Unknown:
Number of moles = ?
Solution:
To find the number of moles, we use the expression below:
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass = 84.01g/mol
Number of moles = [tex]\frac{431.56}{84.01}[/tex] = 5.14mole
5. Determine the number of liters in 4.32 grams of water (H2O). Answer: --_ 5.37L H2O__
Answer:
4.32 [tex]\frac{1}{18.01}[/tex] ×[tex]\frac{22.4}{1}[/tex] = 5.37
Explanation:
22.4 is how many liters per mole. 18.01 is the mass of H2O.
What patterns do you notice between the three maps? Using the concepts
you've learned in this lesson, construct an explanation for these patterns in your
Science Notebook or in the space below.
Answer:
A spatial pattern is a perceptual structure, placement, or arrangement of objects on Earth. It also includes the space in between those objects. Patterns may be recognized because of their arrangement; maybe in a line or by a clustering of points.
Explanation:
The role of an organism in its habitat
A. host
B. prey
C. niche
D. adaptation
Answer:
C. Niche
Explanation:
The role of an organism in it's habitat is it's niche.
A student noticed that the size of the hot pack becomes bigger when magnesium sulfate reacts with water. She thinks that more atoms are produced that make the hot pack grow bigger. Do you agree?
Answer:
No
Explanation:
In the hot pack, as the water reacts with the magnesium sulfate, the pack becomes bigger is not an indication that new atoms have been created or produced.
As with all chemical reactions, they all obey the law of conservation of matter which states that "in chemical reactions, matter is neither created nor destroyed but atoms simply recombine".
The reason why the hotpack becomes bigger is because the atoms gain more volume.
Help!!!!
The diagram represents waves A,B,C, and D traveling in the same medium.Which two waves shown here have the same wavelength
Answer: A and C
Explanation: because wavelength is the distance over which the wave's shape repeats.
Wave A and wave C have the same wavelength as they have the same distance between the two adjacent crests or troughs. Therefore, option (2) is correct.
What are frequency and wavelength?The wavelength of the wave can be defined as the distance between consecutive adjacent points of the same phase on the wave. The separation between the two adjacent crests or troughs on a wave is known as wavelength.
The S.I. unit of the wavelength can be represented in meters. Wavelength is a characteristic of both standing waves and traveling waves, as well as other spatial wave patterns.
The frequency of the wave can be demonstrated as the number of oscillations of a wave in 1 second. The international S.I. units of the frequency can be represented as per second or Hertz.
The relationship between wavelength, speed of light (c), and frequency (ν) is: c = νλ
Therefore, wave A and wave B have the same wavelength in the given diagram.
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